Process for the conversion of difficultly soluble or insoluble carbohydrate ethers into alpha soluble state



Patented June 24, 1930 I p UNITED STATES PATENT orrlca OTTO HUGH S, OIELBERI'ELD," GERMANY, ASSIGNOR TO I. G. FARIBENINDUSTBIEAK'I'IENGESELLSCHAFT, OF FBANKFOBT-ON-THE-MAIN, GERMANY PROCESS FOR mCONVERSION OI DIFI'ICULTLY SOLUBLE OR INSOLUBLE CABBO- HYD'BATE ETHERSINTO A SOLUBLE STATE Io Dra'Iing. Application filed June 84, 1928,Serial No. 118,878, and in Germany June 27, 1925.

In the manufacture of ethers of colloidal carbohydrate, particularly ofcellulose ethers or their transformation products, products areobtainable according to the method of working, which possess either arelatively good solubilit or which are diificultly soluble or insolu le.

The present invention concerns a process for the conversion of suchdiflicultly soluble m or insoluble products into products possessing arelatively good solubility by the use of depolymerizing or degradinagents. This process is carried out by utilizing the action of acids,such as hydrochloric acid, 1

sulfuric acid, phosphoric acid, oxalic acid, a mixture'of zinc chlorideand hydrochloric acid and the like, or other substances exerting adegrading or h drolytic action. At the same time suitabfe additions maybe made, particularly of such compounds, which act on the respectiveethers in a manner causing a solvent or swelling action.

The proportions of acid with respect to the cellulose ether can bevaried within very wide limits.

The following examples serve to illustrate my invention Ewwmple 1.

space of several hours--complete solution is effected. At this point,advantageously after a previous test precipitation, the solution isprecipitated with Water and the prod- 5 not is washed and dried. Afterthistreat ment the cellulose ether has become readily soluble in benzeneand benzene-alcohol. From the solutions in these solvents films areobtainable possessing normal clearness, strength and pliability andcompletely equal to those obtained from the known soluble celluloseethers.. By prolonging the action of the acid (12-24 hours)thesolubility is increased more and more, viscosity of the solutions ofthe product decreasing with increase of solubility.

. Example 2.

1 part by weight of ethyl cellulose, as described in Example 1 istreated with about 10 parts by weight of glacial acetic acid, containingfor example 0.1% of sul huric' acid. 'The further treatment is then eected as described in Example 1.

I claim .1. 'The process which comprises treating a difiicultly solubleether of a colloidal carbohydrate, in the presence of an agent exertinga-swelling action upon the ether, with an acid in suflicient quantity toproduce a degradation of the ether.

2. The process which comprises treating a difiicultly soluble ether of acolloidal car- 'bohydrate, in the presence of an agent exerting aswelling action upon the'ether, with strong inorganic acid in sufliclentquantity to produce a degradation of the ether.

3. The process which comprises treating a diflicultly' soluble ethylether of, cellulose witha mixture of ethyl alcohol, and con- 39centrated sulfuric acid in sufiicient quantity to produce-a vdegradationof the ether. m

4.The process which comprises treating about one part by weight ofadlilicultly soluble ethyl ether of cellulose with a solutionof about 1.5parts by weight of concentrated sulfuric acid in about 3 parts by volumeof alcohol and 3 parts by volume of wateruntil solution is effected. i

5. The process which comprises treating e0 about one part by weight ofan ethyl ether of cellulose contaimng approximately 47 to 48% of ethoxylgroups with a. solution of about 1.5 parts by weight of concentratedsulfuric acid in about 3 arts b volume of alcohol and 3 arts by v0 ume 0water until solution is e ected, thereafter diluting the solution andfiltering and drying the precipitated cellulose compound.

In testimony Whereof'I have hereunto set my hand.

OTTO LEUOHS.

